A 3D shape with all straight edges and flat faces is a polyhedron. Other 3D shapes with least one curved surface are not polyhedra. A 3D shape with regular polygonal faces, meeting at equal angles, is ...

Global warming or just one more torrid estival romance? At left, a cylindrical roxy glass is filled with a tall ice prism. The icy rectangular prism, with square bases, fits snugly in the cylinder.